This is application is a 371 of PCT/FR99/01029 filed Apr. 30, 1999.
The present invention relates to a touch-sensitive matrix screen and more specifically to those constructed by using a plurality of nanotubes.
Traditionally, in computing, the data inputting is carried out by means of a peripheral unit such as a keyboard or a mouse, while the visualisation is obtained by means of a screen of the cathode tube type or of the liquid crystal or plasma type.
Cathode screens are heavy and bulky, and emit a high radiation that is harmful for the user. The liquid crystal display or plasma screens are less bulky, but they are very fragile and do not offer a very high brightness. Furthermore, field effect flat screens are very expensive because the manufacture is necessarily mainly hand-made.
Generally, the fact that the inputting device is normally separated from the visualisation means produces, in computing, a disjunction between the hand which inputs and the sight which controls, unlike writing on paper, where the hand and the eye operate simultaneously at the same place.
To avoid this drawback, touch-sensitive screens, which allow giving orders to a computer by pointing a finger or a stylus on a screen, have been developed. However, these systems are slow and do not allow a very good resolution, for example when inputting a drawing or a text with the help of a stylus. Furthermore, certain flat screens do not tolerate the local pressure, even though it is minimal, of a finger or of a stylus.
The aim of the present invention is to eliminate the above mentioned drawbacks by determining a light flexible touch-sensitive matrix screen allowing a precise inputting.
The invention uses a plurality of nanotubes,
As it is known, the nanotubes are tubes formed by carbon foils arranged in hollow concentric cylinders and were discovered in 1991 by Sumio Lijima. As a reminder, a nanotube is a polymer composed only of carbon and it is a unidirectional periodic crystal.
Many articles regarding the manufacture of the nanotubes have been published. One can, for example, consult the journal LA RECHERCHE num. 307, of March 1998, the journal SCIENCE, Volume 282 of Nov. 6, 1998 or the document WO-A-97/19208. One can also consult the following sites on the Internet (having all of them the prefix http://www.) on the subject of the manufacture and applications of the nanotubes, namely archipress.org, cerca.umontreal.ca/science, research.ibm.com/topics, amsci.org/amsci/articles, amsci/articles, and others.
The invention is situated in this context and allows to remedy the limits of the traditional screens and, consequently, to contribute mainly but not exclusively, to a better use of personal and professional computing. The aim of the present invention is first to determine a touch-sensitive matrix screen not having the abovementioned drawbacks. Another aim of the invention is to determine such a touch-sensitive matrix screen that is not very thick and that is flexible and not very fragile.
These aims are reached, according to the invention, with a touch-sensitive matrix screen for inputting and displaying data comprising a plurality of carbon nanotubes defining a plurality of pixels and a plurality of inputting elements.
According to the invention, this touch-sensitive matrix screen consists of a dot matrix of each dot comprising a pixel and an inputting element, each pixel made up of ends of at least three mutually parallel nanotubes and each transmitting in one of the three primary colours, the input element being made up of the end of at least a fourth nanotube.
Advantageously, each point consists of a plurality of nanotube ends of which at least four are made active.
Preferably, the nanotubes of each point are separated and maintained in position by means of a filler that is, for example, made of a plurality of nonactive nanotubes.
Preferably, each pixel includes a multiple of three active nanotubes respectively connected in parallel.
Preferably also, the end of each active nanotube of each pixel is covered by a luminophore of one of the primary colours